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Title: EFFECTIVE SELECTION OF TRANSGENIC PAPAYA PLANTS WITH THE PMI/MAN SELECTION SYSTEM

Author
item ZHU, YUN - HI AG RESEARCH CENTER
item AGBAYANI, RICHELLE - HI AG RESEARCH CENTER
item MCCAFFERTY, HEATHER - HI AG RESEARCH CENTER
item Albert, Henrik
item Moore, Paul

Submitted to: Plant Cell Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2005
Publication Date: 4/6/2005
Citation: Zhu, Y.J., Agbayani, R., Mccafferty, H., Albert, H.H., Moore, P.H. 2005. Effective selection of transgenic papaya plants with the PMI/Man selection system. Plant Cell Reports. 24:426-432.

Interpretive Summary: Although genetic transformation of plants for improving crop performance requires a separate method for each transformation event to select the transformed cells from among the cells that are not transformed, relatively few methods exist. Collaborative research in Hawaii between the Tropical Plant Physiology Production and Disease Unit of the ARS U. S. Pacific Basin Agricultural Research Center and the Hawaii Agriculture Research Center evaluated a transformation selection protocol for papaya based on overcoming mannose (Man) toxicity with a transgene encoding phospho-mannose isomerase (PMI). The PMI/Man selection system was more efficient than established methods reported using antibiotic selection or with a visual marker. For papaya, the PMI/Man selection system for producing transgenic plants is a highly efficient addition to previously published methods for selection and may facilitate the stacking of multiple transgenes of interest.

Technical Abstract: The selectable marker gene phospho-mannose isomerase (pmi), which encodes the enzyme phospho-mannose isomerase (PMI) to enable selection of transformed cell lines on media containing mannose (Man), was evaluated for genetic transformation of papaya (Carica papaya L.). We found that papaya embryogenic calli have little or no PMI activity and cannot utilize Man as a carbon source; however, when calli were transformed with a pmi gene, the PMI activity was greatly increased and they could utilize Man as efficiently as sucrose. Plants regenerated from selected callus lines also exhibited PMI activity but at a lower specific activity level. Our transformation efficiency with Man selection was higher than that reported using antibiotic selection or with a visual marker. For papaya, the PMI/Man selection system for producing transgenic plants is a highly efficient addition to previously published methods for selection and may facilitate the stacking of multiple transgenes of interest. Alternatively, since the PMI/Man selection system does not involve antibiotic- or herbicide-resistance genes, its use might reduce environmental concerns about potential flow of those genes into related plant populations.